Portable tool



Jan. 15, 1929.

E. H. SHAFF PORTABLE TOOL Filed 0011.1, 1924 2 Sheets-Sheet 1 Jan. l5, 1929.

E. H. SHAF F PORTABLE TOOL Filed Oct. l, 1924 2 Sheets-Sheet 2 Patented Jan. 15, 19h29.

UNiTED STATES PATENT oFF-TCE- ERNEST H. SHAIF, OF GRAND HAVEN; MICHIGAN, ASSIGNOR T0 WM. H. KELLER, INC., f OI GRAND HAVEN, MICHIGAN, A CORPORATION F HICHIGAN.

PORTABLE TOOL.

Application illed October 1, 1924. Serial Io. 741,091.

The invention relates 'generally to portable tools and more especially to tools for performing grinding, scrubbing, polishing, rubbing and allied operations.

While the invention is capable of general application, m improved tool is particularly adapted or use where a liquid such as l water is used in connection with the grinding or'other operation, as in the case of facing concrete structures. In the instance noted, the use of forms during the building of the concrete structure renders it impossible to produce smooth outer faces, and the common practice is to rub the surfaces after the forms have been removed to reduce the ridges, left by the forms, and other roughness, to produce a smooth surface. In per forming this operation it is customary to employ -grinding stones which are applied manually, and water is supplied to the surface being ground so that the grinding operation produces a thin cement-like paste which is forced into the pores and leaves a smooth finished surface. This operation, as performed by hand labor, is exceedingly laborious, and hence is very costly, but Where the surface of the concrete is to be exposed, as in the case of bridge piers, it is essential for the sake of appearance that the operation be performed.

The primary object of my invention, therefore, is to produce a portable tool which is capable of effectually performing the above and allied operations by the applica.- tion of motive power, with a resulting elimination of the laborious character of the operation and a great saving in the time consumed and hence in the cost of the operation.

In attaining this object, I have produced a tool of which a special feature is the delivery of water to the grinding wheel, brush or other device, which discharges into or through such working tool so as to be effectually applied to the working surface. Preferably also the motor is of the pressure fluid actuated type and the motive fluid is utilized to actuate an injector which entrains the Water and supplies it in the desired volume to the working surface.

Another feature of special im ortance in my device is the pi'ovision of a eXible connection between the working tool and the drive shaft or spindle, which greatly facilitates the operation by enabling the operator readily to hold the tool flat upon the surface being fround. f

In t ie o )eration of tools of this character, it is oun( that a high speed is undesirable. Another feature of-my invention, therefore, is the provision of adjustable means for limiting the speed of o eration.

A general object o the invention is to produce a tool .of a thoroughly practical character, of comparatively light weiglit, and yet having ample power to operate the working tool.

In the accom anyin drawings I have illustrated a pre erred orm of my invention, but 1t 1s contemplated that it may be readily be embraced in other structures by those skilled 1n the art without departing from the .spirit and sco e of my invention as expressed in the appen ed claims.

Figure 1 of the drawings is a fragmentary vertical sectional view through a grinder of preferred form.

Fig. is a transverse sectional view taken iapprcximately 1n the plane of line 2 2 of 1g. 3 is a transverse sectional view taken in the plane of line 3 3 of Fig. 1.

Fig. 4 is a detail of o neof the pressure elements.

Fig. 5 1s a transverse Asectional view through the main valve member.

Fig. 6 is a transverse sectional View illustratlng the connection between the valve member and its operating shaft.

Fig 7 1s an enlarged view vof a portion of Fig-1 showing the key connectionv between,the valve and shaft.

Fig. 8 is a View of the. key employed in Fig. 7.

For convenience I have hereinafter described my invention as applied to the grinding of concrete surfaces, but as above indicated, it is not to be understood that the invention is thus limited.

The tool in its preferred form comprises generally a motor of the pressure-fluid-actuated type comprising a casing 7 enclosing a plurality of motor units arranged in circular series and each comprising a cylinder 8 and a piston 9. Five such units are herein shown.

Motive fluid is supplied to the cylinders 8 under the control of an automatic valve mechanism 10 and a manually operable view of the bearing plate valve device' 11, the valve mechanism 10 bein yadapted to permit admlssion of motive fluid to the several cylinders 1n succession and also to permit of the exhaust of the fluid in the operation of the motor, the pressureelements operato with a wabbling motion.

The working tool is in the present 1nstance in the forln of a hollow'grlnding wheel 15 frusto-conical in form, which wheel is driven from the shaft`12 through the medium of a flexible connection generally designated by the numeral 16. The arrangement is such that a water supply tube 17 may be provided axially of the motor, through the shaft, which tube communicates at its rear end with a source of supply at 18. In the present instance a jet of motive fluid discharged by an injector 1nto said supply pipe at the source of supply of the water to entrain the latter and e ect its delivery in the proper volume. Any other suitable method of` causing the water to flow may, of course, be employed.

The motor which I by preference employ is similar in all substantial respects to that illustrated and described in an vapplication of Albert Shinkez, Serial No. 513,244 filed November 7,1921; and the particular valve mechanism which I employ is fully illustrated and described inl my copending application" Serial No. 743,205 tiled October 13, 1924.

The rear end of the casing 7 is in the form of a cylindrical block 20 bored longitudinally to receive bushings constituting the cylinders 8. The rear end of the casing is closed Vby a plate or head 21 which constitutes the rear wall of each of the cylinders. Rigid withthe head 21 is a housing 22 enclosing the valve mechanism 10, and said housing in turn has formed integral therewith a handle 23 providing at its lower portion a passage 24 connected at its rear end with a source of motive fluid supply and controlled by the manually operable valve 11 which may be of any suitable or well known character. Forwardly of the block 20 is a bellshaped casing section 25 secured to theblock by means of bolts 26 passing through the block and anchored in lugs 27 at .the mouthY of tlrejcasing 25. This casing section 25 enclosed/the operative connection between the motor units and the spindle 12. The latter is mounted 'at its rear end in the forward end of the casing section 25 through the medium of ball bearings'28, and at the forward end of a 'tubular extension 29 of the casing section 25, through the medium of a ball bearing 30.

The 'valve mechanism 10 comprises a rotary valve member 31 rotatably mounted in a casing 32 which latter is enclosed inthe housing 22 ri id with the head 21. At the rear end of t e valve member 31 is van annular chamber 33 communicating. at all times with the passage 24, and leading forwardly from said chamber 33 and communicating with a transverse slot 34 is a plurality of ducts 35. The slot 34 is ada ted to communicate successively with .av p urality of ports 36 in the casing 32, one for each of the cylinders and connected to the cylinders by means of outwardly and forwardly. inc ined passages 37. The ports 36 are of relatively large capacity as are also the passages 37, while the slot 34 is formed by a saw-cut and constitutes a restricted passage connecting the ducts 35 and chamber 33 with the ports 36. The valve member also has a transverse slot 38 of substantial width which in the rotation of the valve member communicates respectively withl the ports 36'. Said slot 38 communicates w-ith the interior of the valve member which is tubular in form and at its rear end discharges into an exhaust passage 39 leading to an exhaust chamber 40 opening to the atmosphere/at the upper side of the housing 22. The valve member is rotated in the operation of the grinder in a manner which will hereinafter appear. s

The motive fluid thus supplied successfully to the motor units effects the reciprocatory motion of the pistons 9, which motion is transmitted tothe shaft 12 as above set forth through the medium of the pressure elements 13 and 14. The element 13 is in the form of a ring having on its forward `side a bearing plate 41 shaped to provide sockets 42 to receive balls`43 on thev forward ends ofpiston rods 44 which are connected at their rear ends by ball and socket joints 45 with the pistons. A retaining rin 46 is secured on the forward face of the p ate 41 to maintain the balls 43 in their sockets.

Centrally of the plate 41 ,is formed a bevel' gear element 47 meshing with a stationary gear element 48 mounted coaxially of the casrngj, said intermeshing gears thus constiltute in effect a universal joint holding the pressure' element 13 against rotation but permitting a wabbling motion thereof as it receives the successive impulses of the several motor units. The gear element 48 has a rearward extension 49 which enters a cenj tral bore 50 'in the cylinder block 20. The

rear side of the gear element 48 is provided with diametrically opposite clutch teeth 51 entering grooves in the forward end of the cylinder block' so as to holdv this element against rotation.

The other pressure element 14 is in the form of an inclined plate 52 having a rigid tubular extension 53 mounted at its forward end in the ball bearing 28. The shaft` 12 fits snugly within the tubular extension o3 and is keyed thereto as indicated at 54 so that rotary movement imparted to the element 14 is transmitted to the spindle or shaft 12.

Between the two pressure elements 13 and 14 are interposed bearing balls 55. These transmit the pressure from the element (13 to the element 14 converting the wobbling motion of the former to rotary motion in the latter.

'.lhe shaft 12 extends rearwardly through the pressure elementsv 13 and 14, and through (he gear element 48 and its tubular extension 49 for connection with the valve member 3l to rotate it. The rear end of the shaft 12 is mounted in the cylinder block through the medium of a ball bearing 56 which is held against a shoulder 57 formed in the cylinder block by means of a pair of nuts 58 on the shaft near its rear end. The inner race-ring of the bearing 56 engages a shoulder 59 on the shaft. By this construction the parts are held in assembled relation. The rear end of the shaft` is connected to the valve member through the medium of an annular key member 60 (Fig. 8) having an inturned finger 61 engaging Iin a slot 61a (Fig. 7) in the shaft and a pair of out-turned lingers 62 engaging in grooves or notches 62 in the forward end of the valve member. connection permits' of the easy detachment of the valve member upon a removal of' the head 21.

63 is a counterweight mounted on the tubular extension 53 of the plate 52.

The grinding wheel 15 herein shown is frustro-conical in shape and has a central hole 64 therethrough to receive aftubular eX- tension 65 on a plate 66 bearing against the rear face of the wheel. A plate 67 adapted to bear against the forward face of the wheel has a rearward extension 68 screw-threaded into the member 65. The plate 66 has a rearwardly extending flange 69 to which is screw-threaded a member 7 O which serves rigidly to clamp between it and the plate 66 a plate 71 having a rearwardly extending head 72. Said head is rectangular in form and fits within a similarly shaped socket 7 3 in a semi-cylindrical member 74 fitting within the member 70. It will be seen that the members 70 and 74 constitute in effect a socket and ball, and that the ball is connected to the plate 71 through the medium of a universal joint formed by the rectangular head 72 operating in the socket 73. The head 72 for this purpose is rounded so as to be capable of turning in the ball member 74 on intersecting axes. The ball member 74 has a rearward extension 7 5 which is screwthreaded into a tubular member 76, and the latter in turn is screw-threaded on the forward end of the shaft 12. The tubularjmem- This ber 76 carries a radially extending flange'77 between which and the flange 69 of the plate (36 is interposed a coiled expansion sprin 78. This s ing wheel 1n coaxial.relation to-the shaft and also serves yieldably to hold the ball member 74 in the socket member 70 while permitting thc plate 66 and hence the wheel 15 to flex relative to the shaft 12. 'Eriircling the tubular member 76 and screw-threaded into the forward end of the extension 29 of the cas-ing 25 is a member 79 roviding an annular groove 80 in which 1s enclosed a packing 8l to prevent escape of lubricant from the casing.

It will be seen that the shaftl12 is made tubular in form as are also the axially alined parts associated therewith, to provide a con-- tinuous passage 82 extending through the length of' the grinder. `In this passage I provide a pipe 83 discharging at its forward end into the interior of the wheel/15 and communicating at its rear end with a source of water supply. I have herein shown the pipe formed in two, sections, one extending throughout the length of the shaft and valve, and the other bent/downwardly for connection with an injector 84 which is in turn adapted to be connected with the motive fluid supply and also a source of water supply. The rear or bent pipe section is shown as connected to the longitudinal or main section as indicated at 85 to provide a watertight joint in a wcllknown manner.

The injector 84 comprises a. tubular stem 86 mounted in the lower portion of the handle 23 and interposed inthe air passage 24 but Without cutting off this passage from the source of supply. Said stem has a central upwardly tapering passage 87 communieating at its'larger or upper end with the pipe 83 and at its lower end with a chamber 88 to which water is supplied from the source of supply by a nipple 18. The stem 86 also has a` duct 89 communicating at one end with the air passage 24 and at its other end with a chamber 9() from which leads a restricted port .or jet orifice 91 in a plug 92. Said jet orifice discharges motive fluid at high `velocity into the lower restricted end of the passage 87 and ythus induces a flow of water to the passage 83. The lower end of the injector 84 is provided with a nut 93 in which is mounted a needle valve 94 adapted to control the flow of air from the passage 89 to the jet orifice 91.

For limiting the speed of operation of the grinder I provide a needle valve 95 mounted in a suitable fitting 96 interposed in the passage 24 leading to the valve mechanism. Said fitting has a port 97 therethrough which is controlled by the needle valve 95, the latter being operable by means of a, knurled screw 9 Assuming that the tool is used for surfaciring normally holds the grin I ing a concrete wall, the operation lis as'follows: As soon as the forms have been rei moved from the wall and while the concrete pipe 83 by\the action of motive fluid ad initted to the pipe fromthe. passage 24;'4

through duct 89, chamber 90 and jet 91. It will be observedthat inasmuch as the liquid is discharged into the interior of the iollow wheel 15 it is distributed by the action of centrifugal force over the entire'yvorking surface, effectuallyA moistening it. lf the liquid is applied to the surface from the outside ofthe wheel, much of it runs off and is wasted, andit is very difiieult to maintain on the surface a sufficient amount of moisture. If there is a lack of moisture7 the grinding operation results in the production of a gummy substance which adheres to the face of the wheel, rendering it ineffectual. -On the other hand, with an ample supply of moisture the particles of the concrete removed from the surface of the wall form a ceinent-like paste -which is ground into the pores of the concrete with the result that a smooth and finished surface is produced. A further advantage is that by my t method all of the liquid is utilized' with the result that a smaller volume is required.

By reason of the flexible connection be` tween the grinding wheel and the shaft, the wheel readily conforms to any depressions and elevations in the surface being ground. At the same time the spring acts to distribute the pressure of the Wheel against the wall evenly or uniformly throughout its 'periphery.

I claim as my invention:

l. A portable tool comprising, in combination, a rotary spindle carrying a hollow grinding wheel at one end and havinga passageway therethrough opening into said hollow grinding wheel, a pressure fluid .actuated motor comprising a plurality of motor units offset with respect to the spindle and each Aoperatively associated with the spindle to drive it, valve mechanism for controlling the flowiof pressure fluid Vto said motor units,

means providing a duct supplying pressure fluid tosa-id valve mechanism, and-means communicating with a source of liquid and associated with said pressure fluid duct whereby liquid is drawn from the source of 1,eos,evo

sup ly and dischargedl through said passage rin t e s indle by theaction'ofmpressure fluid Aactuated thereby, said valve mechanism comprising an annular motive f fluid channel, means providmga water supply passage extending through said spindle and said valve mechanism, said passage being located within the annular fluid channel and independent thereof, and means at the rear en d of lthe tool providing a connection between said passage and a sourceof water supply.

3. A portable tool comprising, in combination, a rotary spindle havinga hollow grinding head, a pressure fluid motor operatively connected with said spindle to drive it and including a plurality of motor units arranged in eircumfer'entially spaced relation about the spindle, said spindle having a passageway therethrough arranged to dis charge into the hollow head, an injector communicating with a source of liquid and arranged to discharge into the opposite end of said passageway, and means' for supplying fluid under pressure to the motor and to said injector. f

4. A portable tool comprising, in combination, a pressure fluid actuated motor for driving a working tool, means providing a to the motor, and a fitting mounted on said handle and communicating with a source of liquid supply, said fitting being a part of said liquid supply means and having a port communicating with the motive supply passage and arranged to admit a jet of motive fluid to the liquid supply means whereby to induce the flowv of' liquid therethrough.

5. A portable tool having, in combination, a rotary spindle, a hollow grinding wheel on the spindle, a pressure fluid motor for driving the spindle,a handle for the tool having a passageway therethroughY for pressure fluidy whereby to supply pressure fluid to the motor, said spindle having a passage therethrough arranged to discharge into the hollow grinding wheel, an injector mounted upon the handle and having a discharge port connected with the opposite end of said passageway, a second port communieating with said pressure fluid "passage, and i ERNEST H. SHAFF. 

